KVM are an abbreviation for "keyboard", "video and mouse". A KVM switch is a hardware device that allows a user to control multiple computers from one or more keyboard, video monitor and mouse. With the popularity of USB--USB keyboards, mice, and I/O devices are still the most common devices connected to a KVM switch. Types of KVM Switch include USB Hub Based KVM Switch, Emulated USB KVM Switch, Semi-DDM USB KVM Switch, and DDM USB KVM Switch.